13th International Conference on the Technology of Plasticity (ICTP 2021): High Speed and Impulse Forming I
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Wednesday 9:15 AM
July 28, 2021
Room: Virtual: Room B
Location: Virtual
Session Chair: Anupam Vivek, Ohio State University
Mathematical Model and Quantitative Analysis of Residual Stress Hole during Laser Shock Peening: Xiuquan Cheng1; Junhao Zhang2; Sizhu Cheng1; Chang Yan2; Qinxiang Xia2; 1Guangzhou Civil Aviation College; 2South China University of Technology
Laser shock peening (LSP) can induce residual compressive stress on the component surface, thus improving the fatigue performance of the component. Therefore, LSP has been widely used in aerospace, vehicle engineering and other industrial fields. To research the phenomenon of residual stress hole (RSH) caused by LSP, the “volcano” mathematical model for analyzing the influence factor of RSH was conduct. Quantitative analysis indexes for describing RSH such as relative crater depth, relative crater width, and stress loss ratio were proposed. Based on the reference’s data, a preliminary analysis was performed. The results showed that the main influence factor was the relative crater depth. In order to obtain the best uniform residual stress distribution, overlapping LSP should be used when the relative crater depth is greater than 10%, and the distance between the centers of adjacent spots should be equal to the “crater” radius of the residual stress hole.
The Effects of the Shearing Speed on the Sheared Edge Quality and Edge Cracking: Clare Gu1; Daniel Schoch2; Hyunok Kim1; Fernando Alamos1; John Bornhorst-Home2; 1EWI; 2Airam Press Co. LTD
High-speed shearing was studied to potentially improve sheared-edge quality for steel. The AIRAM pneumatic press can provide significantly higher speed than a conventional press at low energy cost. The maximum speed can reach over 1.5 meters per second depending on equipment setup. The study evaluated the pneumatic press that could increase the slide speed up to 1.5 meters per second. Various grades of steel, BH340, DP780 and Gen-3 980, were sheared using the pneumatic press with two different pressure levels as well as using a conventional press with 0.2 meters per second with the same tooling. The edge quality of the sheared blanks was evaluated using half specimen dome test (HSDT) and micro-hardness. The effects of the high-speed shearing are discussed in this paper.
High-speed Material Characterization Using an Instrumented Forging Hammer: Lander Galdos1; Julen Agirre1; Nagore Otegi1; David Abedul1; Angel Oruna1; 1Mondragon Unibertsitatea
Dynamic testing of materials is needed to model high speed forming processes (i.e. hammer forging) and crash/impact behaviour of structures among others. The most common machines to perform medium to high speed tests are the servo-hydraulic high speed tensile machines and the Hopkinson bars. The paper analyses the possibility to use a laboratory forging hammer for the characterization of materials at medium and high strain rates. For this, a forging hammer has been constructed which is accelerated with a pneumatic cylinder and is able to speed up the anvil up to 6 m/s. Cylindrical specimens have been deformed at different speeds and a high speed camera and an accelerometer have been used to monitor the real specimen strain using DIC and the anvil acceleration respectively. The differences when using both sensors information or only the accelerometer are shown and discussed.
Computational Modeling of Magnetic Pulse Dissimilar Alloys Welding: Aluminum Alloy 6082-T6 and HC420LA Steel: Nélida Rodríguez1; Edurne Iriondo1; Denis Jouaffre2; Franck Girot3; 1University of the Basque Country; 2Plateforme INNOVALTECH; 3IKERBASQUE, Basque Foundation for Science
The use of lightweight materials such as high strength steels, aluminum alloys and composites is increasing. The joints of dissimilar alloys as the Aluminum Alloy 6082-T6 and the HC420LA steel are studied in this work. The selected joining process is the Magnetic Pulse Welding (MPW) which enables to weld these two alloys, being non-joinable by other traditional welding technologies. The technology involves a strong electromagnetic-mechanical-thermal interaction. The investigation will be developed mostly on computational modeling by means of the use of LS-DYNA software, taking into account the key process parameters and their influence. The work will finish presenting experimental results of the cases modelled by finite elements in order to validate the predictive feasibility of the numerical analysis. All the analized cases reached the welding of both blanks and this was confirmed by metallographic characterization. The results show that the simulations developed follow the same geometrical behavior as experimental results.
Shaping of Sharp-edged Design Elements by Electromagnetic Forming: Verena Psyk1; Christian Scheffler1; Albrecht Stalmann1; Martin Goede2; 1Fraunhofer Institute for Machine Tools and Forming Technology; 2Volkswagen Aktiengesellschaft
Modern car body design includes parts with sharp-edged elements, which are challenging for conventional sheet metal forming technologies. Applying high strain rates allows increasing formability for numerous materials including typical aluminium alloys used in the automotive industry. Therefore, integrating high-speed forming into a conventional process can help to extend forming limits. The feasibility of locally sharpening a deep-drawn radius by integrated electromagnetic forming was proved in literature, but up to now only target radii one magnitude bigger compared to the sheet thickness were regarded. The presented paper shows that also target radii in and below the size of the sheet thickness are possible by this process combination. Based on a simplified 2D-component geometry, complementary experimental and numerical investigations served for developing different variants of a modular test tool and analyzing the influence of important process and tool parameters on the forming result.
Advancements in the Simulation of Magnetic Pulse Forming Processes with FORGE(R): José Alves1; François Bay2; Ugo Ripert1; Julien Barlier1; Nicolas Poulain3; 1Transvalor S.A.; 2MINES ParisTech; 3Transvalor Americas
In this work we present the latest developments on the electromagnetic (EM) module of FORGE(R) and the derived improvements for simulating the magnetic pulse forming process. We will cover the following aspects: advanced material description for high intensity magnetic fields; improved meshing/remeshing for large displacements in the fully immersed multi-objects approach and, advanced 2nd order time-stepping integration for accurate computation of the EM fields